function ludou_create_media_category() {
  $args = array(
    'label' => '媒体分类',
    'hierarchical' => true,
    'show_admin_column' => true,
    'show_ui'      => true,
    'query_var'    => true,
    'rewrite'      => true,
  );

  register_taxonomy( 'attachment_category', 'attachment', $args );
}

add_action( 'init', 'ludou_create_media_category' );